Environmental fate processes and biochemical transformations of chiral emerging organic pollutants

This review highlights the analytical chemistry, environmental occurrence, and environmental fate of individual stereoisomers of chiral emerging pollutants, which are modern current-use chemicals of growing environmental concern due to their presence in the environment and potential for deleterious effects. Comparatively little is known about individual stereoisomers of pollutants, which can have differential toxicological effects and can be tracers of biochemical weathering in the environment. Stereoisomers are resolved by gas chromatography (GC), high-performance liquid chromatography (HPLC), and capillary electrophoresis (CE). Separation techniques in environmental analysis are typically coupled to mass spectrometry (MS) and tandem mass spectrometry (MS/MS), as these provide the sensitivity and selectivity needed. The enantiomer composition of phenoxyalkanoic and acetamide herbicides, organophosphorus and pyrethroid pesticides, chiral polychlorinated biphenyl metabolites, synthetic musks, hexabromocyclododecane, and pharmaceuticals in the environment show species-dependent enantioselectivity from biotransformation and other biologically mediated processes affecting enantiomers differentially. These enantiomer compositions are useful in detecting biologically mediated environmental reactions, apportioning sources of pollutants, and gaining insight into the biochemical fate of chiral pollutants in the environment, which are needed for accurate risk assessment of such chemicals.     

Occurrence, fate and determination of cytostatic pharmaceuticals in the environment

We review the literature on the analysis of pharmaceutically-derived cytostatic compounds in the environment. Cytostatics are a major class of chemotherapy drugs used extensively in the fight against cancer. They are a broad group of mostly organic compounds possessing a diverse range of physico-chemical parameters. Their differences and their presence in the environment in trace amounts make their determination in complex matrices a major challenge. Despite the good scientific foundations laid by those in the field, it is apparent that past research has focused mainly on hospital effluents and few have analyzed environmental samples. Importantly, no study has looked at environmental transformation products that, along with human metabolites, could contribute to overall toxicity. To improve understanding of the chemodynamics of cytostatics in natural waters, it is essential to have more data on the occurrence and the fate of these compounds, including their human metabolites and environmental transformation products. This approach will require advanced sampling techniques and state-of-the-art analytical tools, including the latest separation methods and cutting-edge instrumentation.     

Occurrence and chemical speciation analysis of organotin compounds in the environment: A review

Environmental concerns regarding organotin compounds have increased remarkably in the past 20 years, due in large part to the use of these compounds as active components in antifouling paints [mainly tributyltin (TBT)] and pesticide formulations [mainly triphenyltin (TPhT)]. Their direct introduction into the environment, their bio-accumulation and the high toxicity of these compounds towards “non-target” organisms (for example: oysters and mussels) causes environmental and economic damage around the world. As a consequence, the presence and absence of organotin compounds is currently monitored in a range of environmental matrices (e.g., water, sediment and shellfish) to examine the utility of controls meant to regulate the level of contamination as required in some EC Directives and the Water Framework Directive 2000/60/EC. To evaluate the environmental distribution and fate of these compounds and to determine the effectives of legal provisions adopted by a number of countries, a variety of analytical methods have been developed for organotin determination in the environment. Most of these methods include different steps such as extraction, derivatisation and clean up. The aim of the present review is to evaluate the environmental distribution, fate and chemical speciation of organotin compounds in the environment.     

Congener-specific determination of dioxins and related compounds by gas chromatography coupled to LRMS,HRMS, MS/MS and TOFMS

Their characteristics as persistent organic pollutant and their toxicity (2,3,7,8-TCDD is named as a known human carcinogen) make the dioxins and related compounds a focus of interest in environmental analytical chemistry. In view of the widespread distribution of dioxins in the environment, these compounds must be monitored in several matrices, such as air, effluents, soil, sludge and biological samples. The analytical methodologies are especially difficult owing to the complexity of the mixtures of congeners (210 PCDD/Fs and 209 PCBs) and to the low detection limits required (ppb to ppq). Moreover, time-consuming sample preparation steps are needed owing to the presence of a large number of interfering compounds. The different toxicity of each congener requires the development of congener specific methods. This review of trace dioxin determination by mass spectrometry (MS) includes sample preparation and chromatographic separation. In this Special Feature, the use of different MS techniques such as low-resolution MS (LRMS) and high-resolution MS (HRMS) is discussed in terms of selectivity and sensitivity. The performances of other MS techniques, such as tandem MS (MS/MS) and time-of-flight MS (ToFMS), are compared. Quantification techniques, especially the isotopic dilution method, are also discussed. Conclusions and future perspectives are outlined.     

Fate and occurrence of X-ray contrast media in the environment

Interest in the presence of pharmaceuticals in the environment has recently increased. Despite continuous research efforts there is still a large gap in our knowledge of their fate and effects on the ecosystem. This review covers current information on the occurrence of iodinated X-ray contrast media (ICM) in the environment and developments in the analysis of these highly polar organic micropollutants in aqueous environmental samples. Findings from monitoring surveys conducted on wastewater-treatment plants (WWTP), surface waters, and drinking waters are compiled, and strategies for removal of the compounds in WWTP and waterworks using advanced treatment are reported. Characteristics and advantages of different compound-specific or element-specific mass spectrometric techniques used to monitor ICM in the environment are compared, and applications in elucidation of the structures of biotransformation products, generated in laboratory-scale experiments that simulate sewage treatment or river water/sediment systems, are described.     

A review of oxyhalide disinfection by-products determination in water by ion chromatography and ion chromatography-mass spectrometry

This paper is a review of ion chromatographic (IC) separations of inorganic oxyhalide disinfection by-products (DBPs) in water and beverages. The review outlines the chemical mechanisms of formation, regulation of maximum allowable levels, chromatographic column selection and speciation. In addition, this review highlights the application of IC coupled to mass spectrometry (MS) for trace and elemental composition analysis of oxyhalides, along with the analytical considerations associated to enable sensitive analysis. Furthermore, a review of literature concerning IC determination of inorganic oxyhalide DBPs in environmental matrices, including water, published since 2005 is presented, with a focus on MS detection, and a discussion on the relative performance of the methods. Finally some prospective areas for future research, including fast, selective, multi-analyte analysis, for this application are highlighted and discussed.     

Beyond nC60: strategies for identification of transformation products of fullerene oxidation in aquatic and biological samples

Owing to their exceptional properties and versatility, fullerenes are in widespread use for numerous applications. Increased production and use of fullerenes will inevitably result in accelerated environmental release. However, study of the occurrence, fate, and transport of fullerenes in the environment is complicated because a variety of surface modifications can occur as a result of either intentional functionalization or natural processes. To gain a better understanding of the effect and risk of fullerenes on environmental health, it is necessary to acquire reliable data on the parent compounds and their congeners. Whereas currently established quantification methods generally focus on analysis of unmodified fullerenes, we discuss in this review the occurrence and analysis of oxidized fullerene congeners (i.e., their corresponding epoxides and polyhydroxylated derivatives) in the environment and in biological specimens. We present possible strategies for detection and quantification of parent nanomaterials and their various derivatives.     

General applications of fused silica capillary column (FSCC) chromatography to the analysis of non-priority pollutant organics in environmental samples

Further applications of fused silica capillary columns (FSCC) to the analysis of environmental samples are presented. The chromatographic behavior (RT, RRT) of organic compounds of environmental significance not listed as Consent Decree Priority Pollutants is investigated on an SE-54 FSCC. Retention indices (RRT) and mass spectral response factors (RF) are presented for a total of 28 compounds including a number of chloro- and nitro-substituted anilines, alkylpyridines, and alkylquinoline derivatives. The direct application of the FSCC/MS interface to the analysis of these compounds in actual environmental samples is presented, including vent emissions from a fungicide manufacturing process, and contaminated soil and water samples from two metropolitan Boston construction sites.     

Determination of non-steroidal anti-inflammatory drugs in environmental samples by chromatographic and electrophoretic techniques

Non-steroidal anti-inflammatory drugs (NSAIDs) are a group of pharmaceutical compounds widely used in human health care and often found in the aquatic environment, with their metabolites. After an introduction that describes the general problem of drug contamination, the properties of NSAIDs, and environmental risk assessment, this review surveys the chromatographic and electrophoretic methods of analysis in use today for monitoring the most important representatives of this pharmaceutical class in different environmental samples.     

LC-MS analysis in the aquatic environment and in water treatment – a critical review

LC-MS has become an invaluable technique for trace analysis of polar compounds in aqueous samples of the environment and in water treatment. LC-MS is of particular importance due to the impetus it has provided for research into the occurrence and fate of polar contaminants, and of their even more polar transformation products. Mass spectrometric detection and identification is most widely used in combination with sample preconcentration, chromatographic separation and atmospheric pressure ionization (API). The focus of the first part of this review is directed particularly toward instruments and method development with respect to their applications for detecting emerging contaminants, microorganisms and humic substances (HS). The current status and future perspectives of 1) mass analyzers, 2) ionization techniques to interface liquid chromatography (LC) with mass spectrometry (MS), 3) methods for preconcentration and separation with respect to their application for water analysis are discussed and examples of applications are given. Quadrupole and ion trap mass analyzers with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are already applied in routine analysis. Time-of-flight (TOF) mass spectrometers are of particular interest for accurate mass measurements for identification of unknowns. For non-polar compounds, different ionization approaches have been described, such as atmospheric pressure photoionization (APPI), electrochemistry with ESI, or electron capture ionization with APCI. In sample preconcentration and separation, solid phase extraction (SPE) with different non-selective sorbent materials and HPLC on reversed-phase materials (RP-HPLC) play the dominant role. In addition, various on-line and miniaturized approaches for sample extraction and sample introduction into the MS have been used. Ion chromatography (IC), size-exclusion chromatography (SEC), and capillary electrophoresis (CE) are alternative separation techniques. Furthermore, the issues of compound identification, matrix effects on quantitation, development of mass spectral libraries and the topic of connecting analysis and toxicity bioassays are addressed.     

Gas chromatographic retention index as a basis for predicting evaporation rates of complex mixtures

Models that predict the fate of petroleum fuels in the environment are often required for effective remediation of fuel-contaminated sites. In this research, an environmental fuel spill was simulated by means of a diesel/water microcosm, in which the temporal changes in composition were assessed during evaporation by gas chromatography–mass spectrometry (GC–MS). First-order kinetic rate constants were calculated for 51 selected compounds and utilized to develop predictive models for evaporation rate constants, using GC retention indices on a nonpolar stationary phase. Models were initially developed to predict rates of evaporation of compounds from individual classes (normal alkane, branched alkane, alkyl benzene, and polycyclic hydrocarbon) and then expanded to include all compounds (comprehensive model). Using the comprehensive model, the rate constants were predicted with a mean absolute percent error (MAPE) of 10%, whereas the class-specific models resulted in less error (4–8%). These models were employed to predict the fraction remaining of the total fuel (6% error) as well as the fraction remaining of individual compounds (13% MAPE). Accurate models such as these will facilitate remediation of environmental releases of petroleum products.     

Monitoring and characterization of polyaromatic compounds in the environment

This paper provides an overview of analytical techniques and instruments used to monitor and characterize polycyclic aromatic compounds (PACs) in the environment. The basic operating principles of various analytical approaches and systems are presented. The review deals specifically with spectroscopic methods, chromatographic and hyphenated techniques, and field monitoring devices. Emphasis is given to portable devices that can be used under field conditions. Specific examples of analytical techniques and instruments developed in the authors's laboratories will be discussed to illustrate the usefulness and potential of these approaches for environmental monitoring and characterization of PACs.     

Determination of pesticide transformation products: A review of extraction and detection methods

Pesticides are widely applied and they can produce a variety of transformation products (TPs), through different pathways and mechanisms. Nowadays there is a growing interest related to the determination of pesticide TPs in several matrices (environmental, food and biological samples), due to these compounds can be more toxic and persistent than parent compounds, and some of them can be used as markers of exposure to different pesticides. Although solid-phase extraction (SPE) is mainly used for the extraction of TPs, alternative techniques such as solid-phase microextraction (SPME) and liquid-phase extraction (LPE) can be used. These TPs are mainly determined by liquid chromatography (LC) due to the recent developments in this technique, especially when it is coupled to mass spectrometry (MS) detectors, allowing the determination of known and/or unknown TPs. Furthermore, MS is a very valuable tool for the structural elucidation of unknown TPs. This review discusses all phases of analytical procedure, including sample treatment and analysis, indicating the main problems related to the extraction of TPs from several matrices due to their high polarity, as well as the different alternatives found for the simultaneous determination of parent compounds and TPs, using chromatographic techniques coupled to MS detection.     

Analytical Methods for Speciation of Organotins in the Environment

The growing awareness over the environmental fate of organotin compounds is reflected in the large number of analytical methods developed for their separation. Organotin compounds have varying degrees of toxicological properties, depending on the nature and number of alkyl groups bonded to the tin atom. Most of the analytical speciation methods applied to actual environmental media have involved prior derivatization to transform organotin compounds into volatile hydrophobic analytes amenable to separation and identification by gas chromatography coupled to a sensitive and selective tin-detector. Evidence exists that members of the same homologous series are related by environmental degradation pathways. Chemical treatment prior to analysis, or high temperatures associated with gas chromatography separation, may alter the relative amounts of organotins in samples and blur the true environment picture. To avoid species redistribution that may occur during derivatization or gas speciation analysis, methods based on liquid chromatography and supercritical fluid chromatography have been investigated. This review documents analytical methods for determination of tin and speciation of organotin compounds, in the hope that it will be of value to those interested in initiating a programme for assessing the impact of such species on the environment.     

Pharmaceutical residues in environmental waters and wastewater: current state of knowledge and future research

Pollution from pharmaceuticals in the aquatic environment is now recognized as an environmental concern in many countries. This has led to the creation of an extensive area of research, including among others: their chemical identification and quantification; elucidation of transformation pathways when present in wastewater-treatment plants or in environmental matrices; assessment of their potential biological effects; and development and application of advanced treatment processes for their removal and/or mineralization. Pharmaceuticals are a unique category of pollutants, because of their special characteristics, and their behavior and fate cannot be simulated with other chemical organic contaminants. Over the last decade the scientific community has embraced research in this specific field and the outcome has been immense. This was facilitated by advances in chromatographic techniques and relevant biological assays. Despite this, a number of unanswered questions exist and still there is much room for development and work towards a more solid understanding of the actual consequences of the release of pharmaceuticals in the environment. This review tries to present part of the knowledge that is currently available with regard to the occurrence of pharmaceutical residues in aquatic matrices, the progress made during the last several years on identification of such compounds down to trace levels, and of new, previously unidentified, pharmaceuticals such as illicit drugs, metabolites, and photo-products. It also tries to discuss the main recent findings in respect of the capacity of various treatment technologies to remove these contaminants and to highlight some of the adverse effects that may be related to their ubiquitous existence. Finally, socioeconomic measures that may be able to hinder the introduction of such compounds into the environment are briefly discussed.     

Studies of human and veterinary drugs' fate in environmental solid samples--analytical problems

The improvement of medical care worldwide is one of the reasons for the increasing production of pharmaceutical products. Human medicines are affordable to a greater proportion of the world's population. But a significant amount of used pharmaceuticals can create problems--accessibility to high volume production pharmaceuticals contributes to an increased contamination in the environment and the possibility of adverse effects on humans and animals. Many of these substances and their metabolites end up in the soil, sediments, and sludge. Knowledge regarding the environmental occurrence of pharmaceutical products is increasing, but information in the peer-reviewed literature regarding the fate and effects of most pharmaceuticals is limited. One of the reasons for this lack of data is that, until now, there have been few analytical methods capable of detecting these compounds at the low levels, which might be expected in the environment. This review article covers recent developments in the analysis of pharmaceuticals in environmental solid matrices (including soil, sediments, and sludge). We will report applications of different solid sample extraction methods, and current advances in liquid chromatography coupled with mass spectrometry for detection and identification of selected drugs in sludge, soils, manure, and sediments.     

Mass spectrometry for identifying pharmaceutical biotransformation products in the environment

Many classes of pharmaceuticals have been detected in wastewaters and surface waters around Europe, but little is known about their occurrence, fate and potential harmful effects on the environment, and that makes them an important group among those compounds considered to be new emerging contaminants. To understand the cycling of pharmaceuticals and their metabolites, it is essential to possess qualitative and quantitative information on their presence in the environment. This review covers the current status and future prospects of advanced hyphenated mass spectrometric (MS) techniques (gas chromatography-MS (GC-MS) and liquid chromatography-MS (LC-MS)) in elucidating the structures of trace contaminants, namely pharmaceutical biodegradation products in complex environmental matrices. The article is oriented towards technique and method and discusses capabilities, potential and limitations of different GC and LC mass analyzers (quadrupole, ion trap, time-of-flight and hybrid techniques) in dealing with analytical challenges of complex matrices and trace contaminants. We also give practical examples of their applications. The main scope of this article is to support and to facilitate the on-going research on pharmaceutical biodegradation products in environmental samples.     

Occurrence patterns of pharmaceuticals in water and wastewater environments

The occurrence of pharmaceuticals and their metabolites and transformation products in the environment is becoming a matter of concern, because these compounds, which may have adverse effects on living organisms, are extensively and increasingly used in human and veterinary medicine and are released continuously into the environment. A variety of pharmaceuticals have been detected in many environmental samples worldwide. Their occurrence has been reported in sewage-treatment-plant effluents, surface water, seawater, groundwater, soil, sediment and fish. This paper provides an overview of recent scientific research on the sources, occurrence, and fate of pharmaceuticals in water and wastewater.     

Arsenic and its speciation analysis using high-performance liquid chromatography and inductively coupled plasma mass spectrometry

It is known that arsenic has different toxicological properties dependent upon both its oxidation state for inorganic compounds, as well as the different toxicity levels exhibited for organic arsenic compounds. The field of arsenic speciation analysis has grown rapidly in recent years, especially with the utilization of high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS), a highly sensitive and robust detector system. Complete characterization of arsenic compounds is necessary to understand intake, accumulation, transport, storage, detoxification and activation of this element in the natural environment and living systems. This review describes the essential background and toxicity of arsenic in the environment, and more importantly, some currently used chromatographic applications and sample handling procedures necessary to accurately detect and quantify arsenic in its various chemical forms. Applications and work using only HPLC-ICP-MS for arsenic speciation of environmental and biological samples are presented in this review.     

Recent advances in analytical methodologies based on mass spectrometry for the environmental analysis of halogenated organic contaminants

Halogenated organic contaminants, including legislated and potential persistent organic pollutants and their precursors, represent a major environmental concern due to their hazardous effects in humans and wildlife as well as their ability to bioaccumulate through the food chain, their high resistance to environmental degradation, and their long-range atmospheric transport potential. The monitoring of these compounds in the environment at ultra-trace concentration levels requires highly selective and sensitive analytical methodologies. The lack of reference step-by-step methods led to a high number of reliable determinations depending on analytes, the complexity of the sample, and available instrumentation. Thus, this review article is mainly focused on the last advances in the analytical methodologies for the determination of halogenated organic contaminants. Methodologies regarding sample treatment, chromatographic separation, and mass spectrometry analysis have been reviewed to finally highlight the future perspectives for the improvement of the analytical determinations of these compounds and the throughput of environmental control laboratories in this field.